共查询到20条相似文献，搜索用时 31 毫秒
1.
B. Simhadri Rao M. Shanker V. Venkateswar Rao 《Journal of the Indian Society of Remote Sensing》2012,40(3):447-456
Availability of Water resources is not uniform in space and time resulting in deficient and surplus areas. In India, the idea of interlinking of river is proposed for many years to transfer water from surplus regions to water deficient areas. Ken-Betwa river link proposes to transfer 659 MCM of surplus waster from Ken basin to Betwa basin in order to utilise for irrigation and water supply by constructing new projects. Before taking up any new projects feasibility assessment studies are essential. In this context, satellite remote sensing plays vital role in providing required information for the feasibility assessment studies. The processes involved in deriving the satellite based information are explained with Ken-Betwa case study. Using this satellite derived information reservoir submergence analysis and irrigation command analysis were described for one proposed dam site namely Neemkheda. The results of the analysis provide the decision makers to arrive at selection of suitable sites among the proposed dam sites and the final reservoir levels and area that can be irrigated under its command. 相似文献
2.
利用1989、2003、2018年的Landsat影像对安顺市西秀区的地表温度进行反演，分析研究区在30年发展中的热岛时空变化及其成因。使用基于影像的反演算法，结合分类回归树算法进行地表温度的反演，用气象站数据对反演结果进行精度验证，并建立缓冲区对研究区进行相关性分析等定量分析。结果表明：研究区受喀斯特地貌的影响，除主城区外，郊区也存在大量高温区；近30年研究区热效应与不透水面、绿地的面积有极显著相关；1989-2003年研究区城市热岛面积随城市扩张逐渐增大，但2018年主城区城市热岛现象几乎完全消失，排除气象因素和城市形态因子影响的可能后，发现这与安顺市城市绿化的大力进行有密切关系。 相似文献
3.
Efficient water-resource management is essential with regard to food security, growing populations and climate change. This is especially important for low- and middle-income (LMC) countries where food is often locally produced by traditional smallholder farming. Detailed knowledge of the spatio-temporal distribution of irrigation-water consumption provides valuable information to anticipate local food shortages and water scarcity as a result of climate variability. Yet, adequate techniques to quantify irrigation-water consumption at field level over large areas are lacking. Irrigation estimates generally have a coarse resolution making them inadequate for field-level assessments.This study developed a remote-sensing-based approach to quantify spatio-temporal patterns of irrigation-water consumption at field level using the MODIS evapotranspiration product (MOD16A2) and existing land-use maps on the spatio-temporal distribution of irrigated agriculture. Object-based image analysis was used to establish local evapotranspiration differences between irrigated and rainfed fields on a monthly basis, which are the irrigation-water consumption rates of the irrigated fields. This novel method was applied to a study area in the Central Rift Valley in Ethiopia where smallholder farming is dominant and only a few large-scale farms are present. Comparison with irrigation-water-consumption values of a local irrigation scheme showed that the monthly temporal dynamics were captured quite well, but lower values were calculated compared to the scheme's field data. Comparison with two validated remote-sensing based studies in Africa showed good agreement as irrigation-water-consumption estimates were in the same order of magnitude. Irrigation-water consumption follows the temporal rainfall pattern, i.e. irrigation practices intensify with increased water availability. Surface water is commonly used for irrigation in the study area.Our study shows that smallholder practices have a lower irrigation-water consumption compared to modern large-scale farms by approximately a factor 3. Irrigation-water consumption in the area is considerable, especially during the dry season. On average 32 % of excess water (precipitation – evapotranspiration) is consumed for irrigation. For smallholder irrigation and large-scale irrigation specifically this is 28 % and 63 % respectively.The object-based approach presented here is an operational mapping method for field-level irrigation-water-consumption over large areas. MOD16A2 is a global open-source readily-available evapotranspiration product used here although an evapotranspiration product with a higher spatial resolution might be preferred. Our approach can provide irrigation-water-consumption estimates over large areas in data-poor regions, which will increase the understanding of spatio-temporal patterns of smallholder irrigation and provide information to optimize water use. 相似文献
4.
5.
The availability of accurate information on the water consumed for crop irrigation is of vital importance to support compatible and sustainable environmental policies in arid and semi-arid regions. This has promoted several studies about the use of remote sensing data to monitor irrigated croplands, which are mostly based on statistical classification and/or regression techniques. The current paper proposes a new semi-empirical approach that relies on a water balance logic and does not require local tuning. The method stems from recent investigations which demonstrated the possibility of combining standard meteorological data and Sentinel-2 (S-2) Multi Spectral Instrument (MSI) NDVI images to estimate the actual evapotranspiration (ETa) of irrigated Mediterranean croplands. This ETa estimation method is adapted to drive a simplified site water balance which, for each 10-m S-2 MSI pixel, predicts the irrigation water (IW), i.e. the water which is consumed in addition to that naturally supplied by rainfall. The new method, fed with ground and satellite data from two years (2018–2019), is tested in a Mediterranean area around the town of Grosseto (Central Italy), that is covered by a particularly complex mosaic of rainfed and irrigated crops. The results obtained are first assessed qualitatively for some fields grown with known winter, spring and summer crops. Next, the IW estimates are evaluated quantitatively versus ground measurements taken over two irrigated fields, the first grown with processing tomato in 2018 and the second with early corn in 2019. Finally, the IW estimates are statistically analyzed against various datasets informative on local agricultural practices in the two years. All these analyses indicate that the proposed method is capable of predicting both the intensity and timing of the IW supply in the study area. The method, in fact, correctly identifies rainfed and irrigated crops and, in the latter case, accurately predicts the IW actually supplied. The results of the quantitative tests performed on tomato and corn show that over 50 % and 70 % of the measured IW variance is explained on daily and weekly bases, respectively, with corresponding mean bias errors below 0.3 mm/day and 2.0 mm/week. Similar indications are produced by the qualitative tests; reasonable IW estimates are obtained for all winter, springs and summer crops grown in the study area during 2018 and 2019. 相似文献
6.
7.
本文利用自1995年以来的4期DMSP-OLS、NPP-VIIRS夜光遥感影像与Landsat多光谱遥感影像,分析了青岛市近25年的城市建成区范围、各市区边界形态与扩展趋势,并结合土地利用分类、路网、POI、DEM等多源驱动因子及元胞自动机-马尔可夫（CA-Markov）模型,模拟并预测了2027年青岛市土地利用分类。结果表明,近25年青岛建成区扩展主要以外延式为主,其他城区总体上沿胶州湾方向扩展,四周向青岛主城区汇集,主城区建设用地向西北侧发展。本文验证了夜光遥感在监测与预测典型海岸带城市扩张方面的适用性,为城市化发展进程管理与决策提供了重要依据。 相似文献
8.
湖泊提供重要的生产生活用水,在维系生态安全方面发挥显著的价值。中国地理环境复杂多样,湖泊类型各异,不同湖区间的湖泊时空变化特征及驱动机制复杂。两次全国湖泊调查是国家尺度的湖泊变化监测的开创性工作,近年来伴随遥感数据源的海量积累和湖泊遥感提取方法的快速发展,大尺度湖泊水体变化遥感监测研究取得了长足的发展。然而,由于人工判读、湖泊类型判别依据和遥感数据源时相的差异,湖泊水体遥感提取结果及面积估算存在不同程度的出入。首先,本文总结了现有全国尺度湖泊监测研究的遥感数据源、方法和结果,分析了不同研究分析结果差异的可能原因。其次,本文基于1980s—2010s时段Landsat影像制图的湖泊水淹频率数据集的最大水域范围信息,提取并生成了全国湖泊新编目,以其作为该时段内湖泊判定和水体变化监测空间约束的统一参照,避免了因遥感数据时相与年际、年内湖泊水域范围波动对遥感提取结果及湖泊面积计算带来的差异。最后,本文从湖泊水淹范围频度的统计角度,初次提出了可体现湖泊面积年内与年际变化情况的统计指标——概率等效面积,用于监测和指示湖泊水域动态。结果表明,近30年来,中国有3741个最大水域范围大于1 km2的湖泊,总面积约93723 km2,其中青藏高原湖区的湖泊数量约占全国三分之一,总面积超过了全国的一半。全国湖泊总面积呈显著上升趋势,不同湖区的变化趋势差异明显:青藏高原湖区和新疆湖区湖泊面积显著上升,东部平原湖区、内蒙古高原湖区和云贵高原湖区显著下降,东北平原与山地湖区波动式变化、趋势不显著。研究结果总体表明中国湖泊水资源的时空不平衡状况在加剧。 相似文献
9.
本文基于太原市1973-2020年遥感影像,利用人工目视解译结合Google历史影像校正提取建成区,引入紧凑度、扩张强度、扩张速度及重心迁移模型等指标对太原市建成区近50年的时空演变特征进行深入分析,并分析太原市建成区扩张的主要驱动力因素。研究表明：①1973-2020年太原市建成区面积扩张了15.12倍,平均年增长面积为7.85 km2;建成区紧凑度普遍较低,在南北方向扩展明显,重心沿南西约30°方向迁移了约3500 m。②引起太原市建成区扩张的主要因素有经济、人口扩张等,其中国民生产总值与人均GDP起到关键性作用。 相似文献
10.
随着经济的高速发展和城市化进程的加快,如何研究城市扩张的趋势和强度,对城市建筑区规划及促进经济的可持续发展和提高资源利用率具有重大意义。利用监督分类技术方法对城乡建筑区域进行分类,提取出池州市5个时期的建筑区域,并加以比较分析。结果显示,1990-2015年,池州市建筑面积持续增加,城市扩张中心出现向东北部转移的趋势,建筑区域面积逐渐增加,但每年建筑面积增加速率却呈现逐渐下降的趋势,这表明了自然环境对城市扩张的影响。通过结合自然环境、人口、国内生产总值、政策等相关统计资料,经过分析后得到城市扩张与经济和人口有密切的相关关系,但是城市扩张趋势也受制于自然环境的影响,研究结果为城市规划及因地制宜的经济建设提供了理论依据。 相似文献
11.
利用决策树和支持向量机分类方法,基于多期Landsat MSS,TM and ETM+遥感图像和其他辅助数据,对1970s以来近40年半干旱的老哈河流域土地利用变化(land use and land cover change,LUCC)进行动态监测,并利用GIS方法对LUCC进行了定量分析和空间分布制图.结果显示,利用支持向量机分类方法对该地区1976年、1989年、1999年和2007年土地覆盖类型分类可达到较满意的效果;近40年老哈河流域土地利用变化显著,水体和草地减少,城乡用地持续扩张,耕地大幅增加,林地和未利用地大幅度波动、总体减少.LUCC主要发生在林地、草地和耕地之间,表明农、林、牧用地之间转换显著,且在各个时期的空间分布差别较大.从变化强度来看,土地利用的年综合变化率最大值渐趋增大,年均土地动态度在空间分布上差异很大,另外在各研究期赤峰市区周边动态度都很大,反映了赤峰市持续性的城市化进程. 相似文献
12.
本文以天津滨海新区为研究区,以1989年和2009年的Landsat TM遥感影像为数据源,采用综合分类法和二值化方法提取居民用地信息,运用GIS空间分析、扩展面积、扩展强度指数等模型对研究区20年来的居民用地扩展情况进行动态监测,并分析了居民用地方位变化情况,简述了居民用地扩展带来的影响。结果表明,从整体角度看,滨海新区20年来,研究区内的居民用地面积总体扩展了3.35倍,北部发展最快。 相似文献
13.
The Landsat (MSS and TM), SPOT (PLA and MLA) and IRS (LISS-I and LISS-II) images of crop free period (April, May), rainfed crop (October) and rabi irrigated crop (January, February) have been evaluated for their capabilities of mapping (1) primary salt affected soils: (slightly, moderately and severely) (2) saline water irrigated saline soils, (3) sodic water irrigated sodic soils and (4) salt affected soils due to tank seepage in the arid region of Rajasthan. The moderately and severe salt affected soils could be mapped with Landsat, (IRS LISS-I) and SPOT, images of any season. However, the summer season imagery provided maximum extent of salt affected soils. The LISS-II imagery also provided delineation of slightly salt affected soils in addition to the moderate and severely salt affected soils. The delineation of saline and sodic water irrigated areas was possible by using Landsat False Colour Composite for the January month by their characteristic reflectance, existing cropping pattern and the quality of irrigation water being used in the area. The IRS (LISS-II) and SPOT PLA images for the May month were also used for mapping of saline and sodic water irrigated soils. 相似文献
14.
《International Journal of Digital Earth》2013,6(6):534-549
The Qinghai-Tibetan Plateau plays an important role in global climate and environmental change and holds the largest lake area in China, with a total surface area of 36,900 km2. The expansion and shrinkage of these lakes are critical to the water cycle and ecological and environmental systems across the plateau. In this paper, surface areas of major lakes within the plateau were extracted based on a topographic map from 1970, and Landsat MSS, TM and ETM+ satellite images from the 1970s to 2008. Then, a multivariate correlation analysis was conducted to examine the relationship between the changes in lake surface areas and the changes in climatic variables including temperature, precipitation, evaporation, and sunshine duration. Initial results suggest that the variations in lake surface areas within the plateau are closely related to the warming, humidified climate transition in recent years such as the rise of air temperature and the increase in precipitation. In particular, the rising temperature accelerates melting of glaciers and perennial snow cover and triggers permafrost degradation, and leads to the expansion of most lakes across the plateau. In addition, different distributions and types of permafrost may cause different lake variations in the southern Tibetan Plateau. 相似文献
15.
Satellite Remote Sensing, with both optical and SAR instruments, can provide distributed observations of snow cover over extended and inaccessible areas. Both instruments are complementary, but there have been limited attempts at combining their measurements. We describe a novel approach to produce monthly maps of dry and wet snow areas through application of data fusion techniques to MODIS fractional snow cover and Sentinel-1 wet snow mask, facilitated by Google Earth Engine. The method is demonstrated in a 55,000 km2 river basin in the Indian Himalayan region over a period of ∼2.5 years, although it can be applied to any areas of the world where Sentinel-1 data are routinely available. The typical underestimation of wet snow area by SAR is corrected using a digital elevation model to estimate the average melting altitude. We also present an empirical model to derive the fractional cover of wet snow from Sentinel-1. Finally, we demonstrate that Sentinel-1 effectively complements MODIS as it highlights a snowmelt phase which occurs with a decrease in snow depth but no/little decrease in snowpack area. Further developments are now needed to incorporate these high resolution observations of snow areas as inputs to hydrological models for better runoff analysis and improved management of water resources and flood risk. 相似文献
16.
北京周边地区是近一二十a环境退化较严重的地区，特别是由于资源过度开发利用所引起的土地利用和土地覆被变化的生态
环境问题十分突出。以遥感技术、地理信息系统和全球定位系统技术为手段，利用1991或1992年、2001或2002年2期的遥感影像为
基础，辅以土地利用现状图及与生态建设等相关资料，通过外业调查验证，快速、准确地获取北京周边地区51个县级辖区，总土地
面积为23万km2的土地利用现状和近10a的土地利用动态变化及与生态环境相关的土地退化，以反映生态建设工程的实施效果，为
北京周边地区资源合理利用和生态环境建设与规划提供了科学依据。 相似文献
17.
A. V. Suresh Babu V. Venkateshwar Rao I. V. Muralikrishna 《Journal of the Indian Society of Remote Sensing》2007,35(1):81-91
Water Utilisation Index (WUI) defined as area irrigated per unit volume is a measure of water delivery performance and constitutes
one of the important spatial performance indicators of an irrigation system. WUI also forms basis for evaluating the adequacy
of seasonal irrigation supplies in an irrigation system (inverse of WUI is delta, i.e. depth of water supplied to a given
irrigation unit). In the present study WUI and adequacy indicators were used in benchmarking the performance of Nagarjunasagar
Left Canal Command (NSLC) in Andhra Pradesh. Optimised temporal satellite data of rabi season during the years 1990–91 and
1998–99 was used in deriving irrigated crop areas adopting hierarchical classification approach. Paddy is the predominant
crop grown and cotton, chillies, sugarcane etc. are the other crops grown in the study area. Equivalent wet area (paddy crop
area) was estimated using the operationally used project specific conversion factors. WUI was estimated at disaggregated level
viz., distributary, irrigation block, irrigation zone level using the canal discharge data. At project level, WUI estimated
to be 65 ha/MCM and 92 ha/MCM during rabi season of 1990–91 and 1998–99 years respectively. A comparison of total irrigated
area and discharges corresponding to both the years indicate that irrigation service is extensive and sub optimal during 1998–99
and it is intensive and optimal in 1990–91. It was also observed that WUI is lesser in blocks of with higher Culturable Command
Area (CCA) compared to the blocks of lower CCA. All the disaggregated units were ranked into various groups of different levels
of water distribution performance. The study demonstrates the utility of WUI as spatial performance indicator and thus useful
for benchmarking studies of irrigation command areas. The WUI together with satellite data derived spatial irrigation intensity,
crop productivity constitutes important benchmarking indices in irrigation command areas. 相似文献
18.
The India Remote Sensing data on 1:50,000 scale revealed the occurrence of permanent waterlogging in low-lying flats and depressions
of the Indira Gandhi Nahar Pariyojona (IGNP) command area. Such data also indicated seasonal dynamics of waterlogging and
soil salinization (Salt efflorescence/crusting) in irrigated areas. Mixed spectral signatures of high moisture content and
poor crop stand indicated the presence of shallow aquifers close to the main canal. Digital analysis facilitated some indicators
for segregating such land uses, limited to optical range. Ground truth study found patchy crop stand, moist soil profile and
subsurface soil salinization indicating the presence of high water table (<1.5 m). It also found fluctuating (1.5–6.0 m) water
table with poor vegetative growth indicating areas sensitive to waterlogging These were classified as potential waterlogging.
Moderate to high soil salinity was found at surface and at the control section (0.2–0.8 m) of soil profiles indicating initiation
of secondary salinization. Coarse to medium soil texture facilitated capillary rise of salts with the advancing water table
in irrigated zone. The presence of fine textured and impermeable calcium carbonate layers at a depth below the surface enhanced
waterlogging and rise of water table. The preponderance of chlorides and sulfates of sodium, calcium and magnesium was found
in the salinized areas. The quality of ponded water was extremely poor and unfit for its reuse. The ground water was saline
in some areas but normally lies within the prescribed limit. The quality of drainage water was poor in saline depression and
unsuitable for reuse. These were moderate in other areas suggesting its safe reuse if mixed with good quality water. Suitable
soil and water management practices are necessary for sustainable crop production in the irrigated areas 相似文献
19.
受全球气候变化的影响，近年来藏东南区域多数冰川退化加剧，冰湖的异动也更为频繁，冰湖溃决诱发洪水、涌浪、泥石流等山地灾害的风险激增。以多源时序合成孔径雷达（synthetic aperture radar，SAR）影像为数据源，从水体和非水体信号的强度差异出发，开展冰湖的分类方法研究，提出了一种基于时序SAR影像的强度标准化比值实施冰湖提取与动态监测的方法。为了验证方法的可行性，选取日本航天局的ALOS/PALSAR-1与欧空局的Sentinel-1A影像序列，针对位于贡巴冰川流域的典型实验区，在11 a的时间跨度上开展了冰湖动态提取和长时序变化分析。通过实验成功获取了贡巴冰川末端冰湖2007-2018年间的时空变化，进而发现近10 a间冰湖的体量呈高速增长的态势，这从侧面也印证了贡巴冰川消融加剧的现状。此外，2018年的新近监测结果表明，局部溃决涌道的扩张打破了冰湖固有的生存周期，甚至会诱发洪水和泥石流次生灾害的发生，有必要加强监测与防范。 相似文献
20.
利用遥感分类技术能够快速获取土地利用变化信息。基于1996年和2006年两时相的北京城乡结合部地区TM卫星影像数据,采用监督分类和分类后处理方法,对研究区10年间的土地利用变化情况进行了详细分析,得到如下结论:10年间北京城南地区城乡结合部的各种土地利用类型之间相互转化,并以耕地,林地和建设用地相互转化最为显著;耕地和大范围水域面积较大幅度减少,城市居民点及工矿用地和未利用土地面积大幅度地增加,城乡结合部的范围在10年间从北向南进行了大范围地移动。 相似文献